Pneumatic scale.



S. E. HARBACK.

PNEUMATIC SCALE.

APPLICATION PILED JUNI: 17, 1911.

Patented Aug. 19, 1913.

lATTUHIIEYS UNITED s T raue.

STEPHEN n. HARBACK, or roar SMITH, ARKANSAS.

PNEUMATIC SCALE.

Specification of Letters Patent.

Patented Aug. t9,19il3.

Apygxlieation led .Tune 17, 1911. Serial No. 633592.

To all 'whom it may concern:

Be it known that I, STEPHEN E. HARBAGK, a citizen of the United States, residing at Fort Smith, in the county of Sebastian and `State of Arkansas, have invented a- Pneumatic Scale, of which `the following is a specification.

My invention relates to the weighing of merchandise on a scale actuated by some aeriform fluid, preferably air, instead of by a series of beams and weights, or springs, etc., supported on knife-edged bearings; and the objects of my invention are to make a scale,'more durable, and, at the same time, more accurate. I attain these objects by the mechanism illustrated in the accompanying drawing, in which,

Figure l is a vertical section of the scale; Fig. 2 is a Sectionin rear of the mechanism of the scale; Fig. 3 is a front view of the chart-s; Fig. 4 is a detail in front, of the piston.

`Similar letters refer to similar `parts throughout the several views. The base a, in which is the valve 6, and the port c; and the base-plate d, upon which are the perforated seats e; together with the cylinder f, which joins the base at g; serve to form a space about the cylinder and tubes exhausted by means of valve b.

The platform 71., extended downward about the'base, as shown in Fig. l, to protect the oil referred to hereinafter, from dust and cold, is supported on the wall e', which is ribbed vertically to engage the wheels y'. These wheels are at the terminations 'inwardly of the head-plate of the cylinder, and prevent the shifting of the platform when it is loaded. The platform h, and the wall z', are superimposed on the piston la. This piston 7c lis double-plated, and

the space between the plates exhausted by means of the valve Z. These plates are set within, and at the top of, a continuous bandhaving two diameters, see Fig. 4, at neither of which does'the band touch the cylinder. A lower plate is fixed within the band at the junction of the two diameters. This third plate is open in the center for the passage of the barrel of a lifting pump, and serves, with the band m, -see Figs. 1 and 4, at this level perforated, to form the reservoir n, which holds a body of some suitable oil. Cut in the face ofthe band next to the cylinder and on thegreater diameter, where the band has a ridge, is a helical oil of the reservoir n,

yThetubes, with their pistons,

lfer a sealed barometric tube,

groove, the lowest turn of which is on a plane with the ridge, and which carries a spring corresponding to it. Any system of use of piston packing rings may be substituted for the spring. I prefer the spring described. It bears on the walls of the cylinder with a strength less than the gravity of the piston with its superstructure. Through the perforations in the band the Hows to the vestibule, formed by the difference inthe diameters of the band, seev Fig. 4, whence it fills up the spaces about the spring and seals the air within the cylinder and tubes.

Escapementsof oil below the piston ind their way to the bottom ofthe cylinder, and into the cistern at the center of it,'see Fig. 1. The barrel of a lifting pump 0, having a continuous spill-way overhanging the rim of the reservoir, enters the cistern. The pumprod is fast to the under-platt of the piston. Both plates of the piston, as well as the bottom-plate of the cylinder, are made to ac.-

' commodate themselves in shape to the working of the pump, which, when the scale is in action, brings oil from the cistern ervoir, and a circulation of the oil is sustained.

Extending outward and upward from the main-port pis the transmitting tube g, intersected in its length by the barometri tube fr, see Fig. 2. These tubes are closed with snugly fitting pistons ofa different weight one from the other, and each-piston is confined to a given-path by stops-'in the tube. may .be used similarly, for purposes of indication. l preas shown by 1, Fig. 2.' To the outer end of the tube g is suitably fixed a Bourdon pressure gage tubes. Now if yair be pumped into the cylinder and tubes by means of the valve in the cylinder at c, the weights of the two pistons in the tubes, taken together, will counter oise the piston in the cylinder together wi 4li its superstructure. The varying barometric pressures on the platform will cause the piston in the tube 7- to rise and fall in the tube, because this piston is lighter than that in the tube g, and will be therst to register extraneous influences on the confined air. An even pressure is therefore maintained throughout the air in t-he cylinder and tubes. Place merchandise on the platform. An impulse is sent through the conned air, shown to the resby an added movement of the piston in the tube 7. But the piston in the tube g will now move, and compress the air in the Bourdon tube s, which will tend to straighten, and move the indicating mechanism attached to it.

The adjustable, pivoted lever t, F ig. 2, toothed at one end to engage the teeth on -the wheel u, is connected at the other end to the Bourdon tube s. On one side of the wheel u is attached a circular chart, the face of which is partially masked. lt is graduated in pounds and ounces, in sect-ions; and from a' section line is read the fixed crown- -chart lv, also drawn in pounds and ounces,

and showing computations in dollars and cents, all in multi-colored lines.

Those parts of the scale above the base a are sheathed in the framework fw, the space within which is exhausted through perforations in the base by means of the valve b.

I claim in a pneumatic scale:

l. In` a scale for registering weight, a platform, an air chamber a hollow piston therefor arranged to hold a .fluid and proof the air chamber, and means operated by the Bourdon tube for registeringthe weight of a body on the platform.

3. In a scale for registering weight, a platform, an air chamber, a hollow piston therefor arranged to hold a fluid and provided with outlets for permitting the iow of fluid to close the space between the piston and theY walls of the air chamber, a well in `the bottom of said air chamber for receiving fluid which escapes between the piston and the walls of the air chamber, means operated by the movement of the piston forl returning the fluid to the interior of the piston, and means actuated by the air pressure within the chamber for registering the weight of a body on the platform.

4.In a scale for registering weight, a platform, an air chamber, a hollow piston therefor arranged to hold a fluid and provided with outlets lfor permitting the flow of fluid to close the space between the piston and the walls of the air chamber, a well in the bottom of said air chamber for receiving fluid which escapes between the piston and the walls of the air chamber, means operated by the movement of the piston for returning the Huid to the interior of the piston, means actuated by the air pressure within the chamber for registering the Weight of a body on the platform, said means comprising a Bourdon tube having communication with the interior of the air chamber, and a registering device operated by said Bourdon tube.

STEPHEN E. HARBACK.

Witnesses LEWIS BoLIN, Jr., A CONRAD. W. SCHMIEDING. 

